Polyimide derivatives having unsaturated terminal amic acid groups

ABSTRACT

Novel compositions comprising unsaturated polyhemi-amic acid compositions and processes for their preparation are disclosed herein. These new compositions are primarily derivatives of anhydride-terminated aromatic polyimides from which they are prepared by amidation to provide unsaturated amide groups having terminal --CH═CH 2  groups as hemi-amic acid groups or their derivatives. These new compositions are more tractable than the original anhydride-terminated polyimides and can be converted at appropriate lower temperatures to crosslinked, insoluble, infusible polymers without by-product formation thereby extending greatly the applications for which the aromatic polyimides can be employed. Also included are monomeric compounds containing unsaturated amide groups derived from monomeric tetracarboxylic dianhydrides. These are particularly useful as crosslinking agents.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates primarily to new compositions comprising aromaticpolyimides containing terminally unsaturated amide groups as part ofhemi-amic acid or derivative groups. More specifically, it relates tosuch compositions in which the terminal amide groups are moieties thatcontain terminal CH₂ ═CH-- functions capable of polymerizing and formingcrosslinked polymers. Still more specifically, it relates to suchpolyimide hemi-amic acid groups and to the crosslinked polymers obtainedtherefrom without the formation of by-products.

2. State of the Prior Art

Polyimides, as prepared from aromatic dianhydrides and aromaticdiamines, are known to have the desired property of high heat resistanceand high solvent resistance. Such polyimides, upon condensation to aninfusible condition, generate by-products such as water and other vaporsor gases which introduce voids into the fabricated products that detractfrom the expected good physical properties. In addition, because ofthese same desirable properties, they are untractable and therefore verydifficult and expensive to work into desired shapes and forms.

Recent patents, such as U.S. Pat. Nos. 3,879,395 and 3,998,786, aredirected to improving the tractability of the aromatic polyimides byattaching various terminal groups to polyimide oligomers whereby thechains are extended by coupling of the terminal groups. In both of thesepatents the coupling groups are attached as terminal imide moietiescontaining vinyl, propargyl, nitrile, etc. groups. Thus the terminalanhydride group is converted to an imide group containing a vinyl,nitrile, propargyl, etc. group. However in neither of these patents norin any other related prior art reference has there been found anydisclosure that the terminal anhydride group on each end could beconverted to one amide moiety and a second amide or acid or ester moietyof which at least one or both could contain polymerizable structures.The amide groups present in the polyimide derivatives of this inventionare tertiary amides devoid of hydrogen or the amide nitrogen. Thereforeon heating, these amide groups do not convert to imide structures withaccompanying by-product formation and simultaneous loss of crosslinkingfunctionality. Consequently these structures contribute highertractability to the composition and control of the number ofcrosslinking groups to values up to four with functionalities up toeight.

SUMMARY OF THE INVENTION

In accordance with the present invention, it has been found thattractable and curable polyimides may be prepared by converting eachterminal anhydride group in an anhydride-terminated aromatic polyimideto an amide group containing at least one terminal CH₂ ═CH-- group aspart of a hemi-amic acid or derivative group. Moreover it has also beenfound that these compositions have greater tractability than thecorresponding anhydride-terminated and amine-terminated polyimides.Furthermore they can be fabricated and cured at practical temperaturesand pressures to give insoluble, infusible products having improved heatand solvent resistance without by-product formation.

The unsaturated crosslinkable amides of this invention have the formula:##STR1## wherein: Ar' is a tetravalent aromatic organic radical, thefour carbonyl groups being attached directly to separate carbon atomsand each pair of carbonyl groups being attached to adjacent carbon atomsin the Ar' radical except that when the Ar' is a naphthalene radical oneor both pairs of the carbonyl groups may be attached to peri carbonatoms;

Ar is a divalent aromatic organic radical;

n is zero or an integer of at least one, preferably 1-20;

R is an organic moiety having 1-20 carbon atoms including R';

R' is an organic moiety containing 2-14 carbon atoms and having aterminal --CH₂ ═CH-- structure;

Y" is OH or X, and

X is halogen, preferably chlorine or bromine.

The amides (I) are conveniently prepared by amidation of the anhydride:##STR2## or the anhydride-terminated compound (II) of the formula:##STR3## wherein Ar' is a tetravalent aromatic organic radical,preferably containing at least one ring of six carbon atoms, said ringbeing characterized by benzenoid unsaturation, the four carbonyl groupsbeing attached directly to separate carbon atoms and each pair ofcarbonyl groups being attached to adjacent carbon atoms in the Ar'radical except that when Ar' represents the naphthalene radical one orboth pairs of carbonyl groups may be attached to peri carbon atoms.

When the n in Formula II is zero, the formula becomes that of thedianhydride shown at the beginning of the paragraph. When n is one ormore, Formula II contains two or more imide groups and representspolyimides used in this invention.

Amidation of (II) occurs in the terminal anhydride function first withthe formation: ##STR4## of a hemi-amic acid (III) which by continuedamidation, yields the diamide (IV): ##STR5## or by esterification yieldsthe amide esters (V) which are useful per se or by interchange withHNRR' can be converted to amide structures (IV): ##STR6##

In some cases, such as when vinyl esters are desired in (V),transesterification may be used with vinyl esters such as vinyl acetateor vinyl benzoate to introduce a terminal vinyl structure, e.g.:##STR7## In the vinyl ester the R" represents the hydrocarbon residue ofan acid group such as ethyl in acetic acid, phenyl in benzoic acid, etc.

With regard to esterifications with alcohols that polymerize actively,particularly if heated, such as the vinyl benzyl alcohols, it isdesirable to conduct all or part of the esterification by converting theanhydride or hemi-amic acid to the corresponding acid halide andperforming the esterification at lower temperatures, e.g., at or belowroom temperature, thus: ##STR8##

Alternatively, esterification can also be achieved by reacting a metalsalt derivative of the terminal anhydride or hemi-amic acid group withan alkyl sulfate, e.g.: ##STR9##

Alternatively, the anhydride function can be converted to thecorresponding acid chloride (VII): ##STR10## which is convertible to VIby reaction with HNRR' and by continued reaction with HNRR' to (IV) orwith ROH to (V).

Also the amides of this invention may be prepared by amidating anamine-terminated compound of the formula VIII: ##STR11## wherein Ar, Ar'and n has the same meaning as in Formula I with an unsymmetricalaromatic anhydride of the formula: ##STR12## wherein Y represents NRR'and Y' represents NRR or OR. Thus: ##STR13##

The amine-terminated compounds (VIII) used hereinabove as intermediatesin the preparation of the amides (I) of this invention as illustrated byEquation 8, are preferably oligomers prepared by reacting a molarexcess, i.e., n+1 moles of an aromatic diamine, H₂ NArNH₂, with n molesof an aromatic dianhydride ##STR14## wherein Ar and Ar' have the samemeaning as defined heretofore and the aromatic diamines and the aromaticdianhydrides are similar pairs of co-reactants used to prepare theanhydride-terminated compounds represented by Formula II. Polyimideamine-terminated oligomers of Formula VIII useful as intermediates maybe conveniently prepared by the same process used to synthesizeanhydride-terminated polyimides of Formula II except for the molar ratioof amine and anhydride used. Syntheses of the amine-terminated andanhydride terminated polyimide oligomers are exemplified in U.S. Pat.Nos. 3,897,395 and 4,058,505 and also hereinafter with specificreference, for example, to the synthesis of the anhydride-terminatedpolyimides.

Anhydride-terminated polyimides of Formula II used in the abovereactions in the synthesis of polyimide-amides of this invention areprepared by reacting a molar excess, i.e., n+1 moles of an aromaticdianhydride with n moles of an aromatic diamine. The aromaticdianhydride has the formula: ##STR15## wherein Ar' is a tetravalentorganic radical, preferably containing at least one ring of six carbonatoms, said ring characterized by benzenoid unsaturation, the fourcarbonyl groups being attached directly to separate carbon atoms andeach pair of carbonyl groups being attached to adjacent carbon atoms inthe Ar' radical except that when Ar' represents the naphthalene radical,one or both pairs of carbonyl groups may be attached to the peri carbonatoms.

The aromatic diamines useful in this preparation are represented by theformula H₂ N--Ar--NH₂ wherein Ar is a divalent aromatic organic radical.

In preparing the anhydride-terminated polyimides, any of the aromatictetracarboxylic acid dianhydrides known in the prior art can be used.Among the useful dianhydrides are 3,3',4,4'-benzophenonetetracarboxylicacid dianhydride, pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 1,4,5,6-tetracarboxylic dianhydride,3,3',4,4'-diphenyl tetracarboxylic acid dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid dianhydride, 2,2',3,3'-diphenyl tetracarboxylicacid dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride,3,4,9,10-perylene tetracarboxylic acid dianhydride,bis(3,4-dicarboxyphenyl)ether dianhydride,naphthalene-1,2,4,5-tetracarboxylic acid dianhydride,2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 3,4,9,10-perylenetetracarboxylic acid dianhydride, bis(3,4-dicarboxyphenyl) etherdianhydride, naphthalene-1,2,4,5-tetracarboxylic acid dianhydride,naphthalene-1,4,5,8-tetracarboxylic acid dianhydride,decahydronaphthalene-1,4,5,8-tetracarboxylic acid dianhydride,4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylicacid dianhydride, 2,6-dichloronaphthalene-1,4,5,8-tetracarboxylic aciddianhydride, 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic aciddianhydride, 2,3,6,7-tetrachloronaphthalene-1,4,5,8-tetracarboxylic aciddianhydride, phenanthrene-1,8,9,10-tetracarboxylic acid dianhydride,cyclopentane-1,2,3,4-tetracarboxylic acid dianhydride,pyrrolidine-2,3,4,5-tetracarboxylic acid dianhydride,pyrazine-2,3,5,6-tetracarboxylic acid dianhydride,2,2-bis(2,3-dicarboxyphenyl)propane dianhydride,1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride,1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride,bis(2,3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)sulfone dianhydride, andbenzene-1,2,3,4-tetracarboxylic acid dianhydride. The first threementioned dianhydrides are preferred.

Aromatic diamines useful in preparing the starting polyimides have theformula:

    NH.sub.2 --Ar--NH.sub.2

wherein Ar is a divalent aromatic organic radical. Preferred aromaticdiamines are those wherein Ar is a divalent benzenoid radical selectedfrom the group consisting of: ##STR16## and multiples thereof connectedto each other by R^(III), e.g., ##STR17## wherein R^(III) is --CH═CH--;##STR18## or an alkylene chain of 1-3 carbon atoms, wherein R^(V) andR^(VI) are each selected from the group consisting of alkyl and arylcontaining one to six carbon atoms, e.g., methyl, ethyl, hexyl, n-butyl,i-butyl and phenyl. Preferred Ar' groups are: ##STR19##

Examples of the aromatic diamines which are suitable for use in thepresent invention are 4,4'-diaminodiphenyl propane,4,4'-diamino-diphenyl methane, benzidine, 3,3'-dichlorobenzidine,4,4'-diamino-diphenyl sulfide, 3,3'-diamino-diphenyl sulfone,4,4'-diamino-diphenyl sulfone, 4,4'-diamino-diphenyl-diphenylsilane,4,4'-diamino-diphenyl ethyl phosphine oxide, 4,4'-diamino-diphenylphenyl phosphine oxide, 4,4'-diamino-diphenyl N-methyl amine,4,4'-diamino-diphenyl N-phenyl amine and mixtures thereof,3,3'-dimethyl-4,4'-diaminodiphenylmethane,3,3'-diethyl-4,4'-diaminodiphenylmethane,3,3'-dimethoxy-4,4'-diaminodiphenylmethane,3,3'-diethoxy-4,4-diaminodiphenylmethane,3,3'-dichloro-4,4',4,4'-diaminodiphenylmethane,3,3'-dibrome-4,4'-diaminodiphenylmethane,3,3'-dicarboxy-4,4'-diaminophenylmethane,3,3'-dihydroxy-4,4'-diaminophenylmethane,3,3'-disulpho-4,4'-diaminodiphenylmethane,3,3'-dimethyl-4,4'-diaminodiphenylether,3,3'-diethyl-4,4'-diaminodiphenylether,3,3'-dimethoxy-4,4,'-diaminodiphenylether,3,3'-diethoxy-4,4'-diaminodiphenylether,3,3'-dichloro-4,4'-diaminodiphenylether, 3,3'-dibromo-4,4'-diaminodiaminodiphenylether, 3,3'-dicarboxy-4,4'-diaminodiphenylether,3,3'-dihydroxy-4,4'-diaminodiphenylether,3,3'-disulfo-4,4'-diaminodiphenylether,3,3'-dimethyl-4,4'-diaminodiphenylsulfide,3,3'-diethyl-4,4'-diaminodiphenylsulfide,3,3'-dimethoxy-4,4'-diaminodiphenylsulfide,3,3'-diethoxy-4,4'-diaminodiphenylsulfide,3,3'-dichloro-4,4'-diaminodiphenylsulfide,3,3'-dibromo-4,4'-diaminodiphenylsulfide,3,3'-dihyroxy-4,4'-diaminodiphenylsulfide,3,3'-disulfo-4,4'-diaminodiphenylsulfide,3,3'-dimethyl-4,4'-diaminodiphenylsulfone,3,3'-diethoxy-4,4'-diaminodiphenylsulfone,3,3'-dichloro-4,4'-diaminodiphenylsulfone,3,3'-dicarboxy-4,4'-diaminodiphenylsulfone,3,3'-disulfo-4,4'-diaminodiphenylsulfone, 3,3-diaminodiphenylsulfone,3,3-diethyl-4,4'-diaminodiphenylpropane,3,3,'-dimethoxy-4,4'-diaminodiphenylpropane,3,3'-dibromo-4,4'-diaminodiphenylpropane,3,3'-dichloro-4,4'-diaminodiphenylpropane,3,3'-dicarboxy-4,4'-diaminodiphenylpropane,3,3-dihydroxy-4,4'-diaminodiphenylpropane,3,3'-disulfo-4,4'-diaminodiphenylpropane,3,3'-dimethyl-4,4'-diaminobenzophenone,3,3-dimethoxy-4,4'-diaminobenzophenone,3,3'-dichloro-4,4'-diaminobenzophenone,3,3'-dibromo-4,4'-diaminobenzophenone,3,3'-dicarboxy-4,4'-diaminobenzophenone,3,3'-dihydroxy-4,4'-diaminobenzophenone,3,3'-disulphodiaminobenzophenone, 3,3'-diaminodiphenylmethane,3,3'-diaminodiphenylether, 3,3'-diaminodiphenylsulfide,3,3-diaminodiphenylsulfone, 3,3-diaminodiphenylpropane,3,3'-diaminobenzophenone, 2,4-diaminotoluene, 2,5-diaminotoluene,1-isopropyl-2, 4-phenylenediamine, 2,4-diaminoanisole,2,4-diaminomonochlorobenzene, 2,4-diaminofluorobenzene,2,4-diaminofluorobenzene, 2,4-diaminobenzoic acid, 2,4-diaminophenol and2,4-diaminobenzenesulfonic acid and phenylene diamines. Preferreddiamines are 4,4'-oxydianiline, 4,4'-sulfonyldianiline, 4,4'-methylenedianiline, 4,4'-diaminobenzophenone, 4,4'-diaminostilbene and thephenylene diamines, 2,4-diaminotoluene and all the meta and para isomersof N₂ NC₆ H₄ OC₆ H₄ OC₆ H₄ NH₂.

The monoamines used in introducing the CH₂ ═CH-- containing tertiaryamide groups (devoid of hydrogen atoms on the nitrogen atoms) into thepolyimides of this invention are secondary amines and are represented bythe formula HNRR'. The hydrogen attached to the secondary amine iseliminated in the reaction that forms the amide.

In HNRR', R' and R have the same meaning as defined for Formula (I). Afew typical examples of such amines are: ##STR20##

A few illustrative examples of R', that is, an organic moiety containing2 to 14 carbon atoms and a terminal --CH═CH₂ group are:

CH₂ ═CH, CH₂ ═CH--CH₂ --, CH₂ ═CHCH(CH₃)--, CH₂ ═CHC₆ H₄ --, CH₂ ═CHC₆H₄ CH₂ --, CH₂ ═CHCH₂ CH₂ C₆ H₄ --, CH₂ ═CHCH₂ C₆ H₄ --, CH₂ ═CHCH₂ C₆H₄ CH₂ --, CH₂ ═CHC₆ H₄ OC₆ H₄ --, CH₂ ═CHC₆ H₄ SO₂ C₆ H₄ --, CH₂ ═CHC₆H₄ OCH₂ CH₂ CH₂ CH₂ --, CH₂ ═CHC₆ H₄ OCH₂ CH₂ CH₂ CH₂ CH₂ --, CH₂═CHOCH₂ CH₂ --, CH₂ ═CHOCH₂ CH₂ CH₂ --, CH₂ ═CHOC₆ H₄ --, CH₂ ═CHCH₂ OC₆H₄ --, CH₂ ═CHOC₆ H₄ OCH₂ CH₂ --, CH₂ ═CHOC₆ H.sub. 4 OCH₂ (CH₂)₄ CH₂--, CH₂ ═CHOOCC₆ H₄ --, etc. For reasons of economy and commercialavailability of intermediates for synthesis, the preferred R' groups areCH₂ ═CH--, CH₂ ═CHC₆ H₄ --, CH₂ ═CHC₆ H₆ -- and CH₂ ═CHC₆ H₄ CH₂ --.

The corresponding hydroxy compounds have the formula R'OH and areclassified as alcohols or phenols and are used to introduce ester groupsinto the compositions of this invention as shown hereinabove. In thecase of the vinyl groups the CH₂ ═CH-- group is introduced as indicatedabove by means of the esters of vinyl alcohol, namely the vinyl estersCH₂ ═CHOCOR' wherein R' is any hydrocarbon moiety containing 1 to 20carbon atoms, preferably 2 to 6 carbon atoms as represented by vinylacetate, vinyl benzoate, vinyl butyrate, etc.

Illustrative examples of R are, in addition to R', the organic moietiescontaining 1 to 20 carbon atoms, e.g.: --CH₃, --CH₂ CH₃, --CH₂ CH₂ CH₃,HC(CH₃)₂, --CH₂ CH₂ CH₂ CH₂, ##STR21## --CH(CH₃)CH(CH₃)₂, --(CH₂)₄ CH₃,--CH₂ CH(C₂ H₅)₂, --CH₂ CH═CHCH₃, --(CH₂)₁₁ CH₃, --(CH₂)₁₉ --CH₃, --C₆H₅, --C₆ H₁₁, --C₆ H₄ CH₃, --C₆ H₄ C₆ H₅, --C₁₀ H₇, --CH₂ CH₂ OC₆ H₅,--CH₂ C₆ H₄ SO₂ C₆ H₅, --CH₂ CH₂ OOCC₆ H₅, --CH₂ C₆ H₅, --CH₂ C₆ H₁₁,--CH₂ C₁₀ H₇, etc. The corresponding hydroxy compounds have the formulaROH.

Monoamines which may be used to introduce a second amide group into thepolyimides of this invention without introducing another vinyl grouphave the formula HNRR in which neither R is R'. However R can containCH.tbd.C-- or --C.tbd.C-- moieties, some examples of which are:CH.tbd.CCH₂ --, CH.tbd.C--CH(CH₃)--, CH.tbd.CCH₂ CH₂ --, CH.tbd.CC₆ H₄,CH.tbd.CC₆ H₄ CH₂ --, CH.tbd.CCH₂ CH₂ C₆ H₄ --, CH.tbd.CCH₂ C₆ H₄ CH₂--, CH.tbd.CC₆ H₄ OC₆ H₄ --, CH.tbd.CC₆ H₄ SO₂ C₆ H₄, CH.tbd.CC₆ H₄ OCH₂CH₂ CH₂ CH₂ --, CH.tbd.CC₆ H₄ OCH₂ CH₂ CH(CH₃)CH₂ --, CH.tbd.CCH₂ OCH₂CH₂ --, CH.tbd.CCH₂ OCH₂ CH₂ CH₂ --, CH.tbd.CCH₂ OC6H₄ --, CH.tbd.CCH₂CH₂ OC₆ H₄ --, CH.tbd.CCH₂ CH(CH₃)C₆ H₄ OCH₂ CH₂ --, CH.tbd.CCH₂ OC₆ H₄OCH₂ (CH₂)₃ CH₂ --, CH.tbd.CCH₂ OOCC₆ H₄ --, CH.tbd.CCH₂ OOCCH₃, etc.

The polyimide starting materials used in the process of this inventionmay be prepared conveniently as shown in U.S. Pat. Nos. 3,897,395 and4,058,505 by reacting the dianhydride with the diamine in a phenolsolvent of the formula: ##STR22## where each R^(I) is hydrogen or amethyl radical in the presence of certain organic azeotroping agents,particularly cyclic hydrocarbons of 6 to 8 carbon atoms and mostpreferably benzene or toluene until most of the water of reaction iseliminated. The reaction temperature is less than 140° C. and alsoshould be below the boiling point of the phenol used but higher than theboiling point of the azeotroping agent. The vapor phase temperature liesbetween that of the water azeotrope and no higher than 95° C. As thewater of reaction and azeotroping agent are removed from the reactionmixture, quantities of the azeotroping agent are returned to thereaction mixture so as to maintain the temperature and reaction mixturevolume substantially constant. It is preferred that the process becontinuous with continuous removal of water and continuous return ofazeotroping agent. This is conveniently done by the use of aconventional Dean-Stark trap and condenser wherein after the azeotropecondenses, the water preferably sinks to the bottom of the trap forsubsequent removal and the azeotroping agent overflows the trap andreturns to the reaction mixture. Initially the trap is filled withazeotroping agent. For brevity, this apparatus will be referred toherein as cresol-benzene azeotropic apparatus.

By using an excess of the anhydride, the terminal groups of thepolyimide will be anhydride groups. The more excess there is of theanhydride, the shorter will be the molecular length. Advantageously theamount of excess anhydride is calculated in accordance with the desiredlength or molecular weight of the desired starting polyimide.

The products of this invention can be converted to the insoluble,infusible state by heat alone, such as by heating at temperatures in therange of 200° C. to 350° C., or even at lower temperatures, such as 100°C. to 200° C., or, if desired, by the addition of catalysts thatgenerate free radicals, such as benzoylperoxide, the perbenzoates, cumylmono and diperoxides, and a host of others that are well known in thevinyl monomer art, which include redox systems which promotepolymerization of CH₂ ═CH-- containing monomers at or even below roomtemperature, or by ionizing radiation or ultraviolet radiation, etc.

These products can be compounded with fillers of all sorts in thepreparation of molding compounds, such as with graphite and quartzfibers or fillers to maintain high temperature resistance, etc.

The hemi-amic acids and derivatives of this invention are particularlyuseful as coatings and bonding agents for metals such as iron, copper,aluminum, steel, etc. either alone or as mixtures with the tetraamidescontaining two to four terminal CH₂ ═CH-- structures. Also important isthe fact that these new polyamides copolymerize with polyimides notcontaining terminal amide groups but imide structures which haveterminal CH₂ ═CH--, CH.tbd.C-- or ##STR23## a number of which aredisclosed in U.S. Pat. No. 3,998,786.

The new polyimide amides of this invention can be used as varnishes andcoatings in appropriate solvents which depend on the nature of theconstituent diamine and dianhydrides used in the synthesis of thepolyimide amides.

In most cases the solvent is an aprotic organic compound having adielectric constant between 35 and 40, preferably one which is watersoluble. Representative aprotic compounds are: N,N-dimethylformamide,N,N-diethylformamide, N,N-dimethylmethoxyacetamide, N-methylcaprolactam, caprolactam, N,N-dimethylacetamide, N,N-diethylacetamide,dimethyl sulfoxide, N-methyl-α-pryyolidone, tetramethylurea,hexamethylphosphonamide, tetramethylene sulfone,N,N,N',N'-tetramethylethylmalonamide, N,N,N',N'-tetramethyl glutaramide,N,N,N',N'-tetramethylsuccinamide, thiobis(N-dimethylacetamide),bis(N,N-dimethylcarbamylmethyl)ether, N,N,N'N'-tetramethylfuraramide,methylsuccinonitrile, N,N-dimethylcyanoacetamide,N,N-dimethyl-β-cyano-propionamide, N-formyl-piperdine and butyrolactone,etc.

Of the solvents, dimethylacetamide is most preferred. Other preferredsolvents are dimethylformamide, N-methyl pyrrolidone, dimethylsulfoxide, butyrolactone and caprolactum.

In many cases, non-aprotic solvents can be used. For example, xylene,phenol, anisole, benzonitrile, acetophenone, methylphenylether,methylene chloride, chloroform, carbon tetrachloride or mixtures ofthese with each other, the aprotic solvents or with relatively poorsolvents such as benzene, toluene, cyclohexane, cyclohexene, dioxane,butyl cellosolve and the like.

In the practice of this invention the specific nature of Y and Y" inFormula I is very important in avoiding the formation of by-productswhich are retained and detrimental when the compositions of Formula Iare subjected to thermal treatment either to achieve curing andcrosslinking of this composition, or after curing, when the compositionis subjected to the long term stress of high temperatures in aparticular application of the formed, cured fabricated parts such as inmoldings, laminated products, fiber-reinforced shapes, wire and otherfilament coated products, etc. For example, if a primary amine H₂ NR' isused instead of HNRR' in Eq. 1 in the formation of hemi-amic acid, thishemi-amic acid, when heated, will imidize with the elimination of H₂ Oas illustrated below: ##STR24## This imidization will occur even if the--COOH function is changed to --COOR, --COOR', --CONHR, --CONHR',--CONRR', CONRR, --CONRR', --COX as long as there remains an activeamide hydrogen in the --CONHR' moiety, thus:

    ______________________________________                                        CONHR'                                                                        Ar                                                                                    ##STR25##     (XII) + ROH                                                    (COOR)                                                                 "      (COOR')   "        (XII) + R'OH                                        "      (CONHR')  "        (XII) + H.sub.2 NR'                                 "      (CONHR)   "        (XII) + H.sub.2 NR' + H.sub.2 NR                    "      (CONHR')  "        (XII) + H.sub.2 NR'                                 "      (CONRR')  "        (XII) + HNRR'                                       "      (CONRR)   "        (XII) + HNRR                                        "      (CONRR')  "        (XII) + HNRR'                                       "      (COX)     "        (XII) + HX                                          ______________________________________                                    

In contrast, when Y and Y' are as defined in the practice of thisinvention, imidization does not occur: ##STR26## and the Y' moietiesfunction to produce crosslinkages without the formation of by-products.

A particular advantage accrues to the practice of this invention. It isobvious that in polyimides that depend for crosslinking on terminalimide functional groups, as for example: ##STR27## etc., there are onlytwo polymerizable crosslinking groups per polymer chain, and as thechain length increases as it does with an increase in the value of n asin (I), the crosslink density, i.e., the number of crosslinks per nnumber of segmers, decreases and the heat distortion value of thecomposition under load decreases. It is desirable therefore, to be ableto increase the crosslink density of such composition. This is nowachieved by converting the terminal anhydride groups to Y and Y' whichcannot imidize. The products have chains with only one crosslinkingfunction at each end of the chain. By the practice of this invention, itis possible, if desired, to adjust the crosslink density as a functionof only one crosslinking moiety at the end of each chain to as high asfour at each end, or a total of eight for each chain, as shown in suchstructures as: ##STR28## In addition, the increased number of suchfunctional groups contribute to an increase in the rate of curing whichhas industrial economic importance.

The composition of this invention finds utility in the broad field ofpolyimide technology as in molding compounds, laminated products asimpregnants for porous bodies, varnishes for a wide variety ofsubstances including sheets, filaments, etc. of metals, glass, carbons,encapsulating compounds, etc.

SPECIFIC EMBODIMENTS OF THE INVENTION

The invention is illustrated by the following examples which areintended merely for purpose of illustration and are not to be regardedas limiting the scope of the invention or the manner in which it may bepracticed. Unless specifically indicated otherwise, parts andpercentages are given by weight.

EXAMPLE I Preparation of Anhydride-Terminated Oligomeric Polyimide #1

Into a 100 ml three-neck, round bottom flask equipped with a magneticstirrer, thermometer, condenser, gas inlet tube, dropping funnel, etc.there is placed under nitrogen atmosphere a solution ofbenzophenone-tetracarboxylic acid anhydride (BTCA) (6.44 g, 0.02 mole)in 25 ml of dimethylacetamide (DMAC). Then a solution of4,4'-oxydianiline (ODA) (2.00 g, 0.01 mole) in 15 ml of DMAC is addedover a period of 15 minutes. The reaction, which is exothermic, ismaintained at 40° C. during the addition following which it is heated at85° C.-90° C. for 15 minutes. To this clear amber-coated solution,acetic anhydride (3.06 g, 0.03 mole) is added and the mixture is heatedto 125° C. Within 15 minutes, a yellow precipitate is formed. Afterheating the reaction mixture for one hour the solvents are removed in arotary flash evaporator. The residual light yellow solid is washed withanhydrous ether and dried in a vacuum oven at 140° C. to afford aquantitative yield. It softens slightly on a Fisher-Johns melting pointapparatus at 120° C. and does not melt when heated to 300° C. Theproduct is soluble in m-cresol and N-methyl-2-pyrrolidone and onlyslightly soluble in boiling benzonitrile, acetophenone or DMAC. Theelemental analysis is found to be for C: 68.3% and for H: 2.4%, whichare in good agreement with the calculated values for C₄₆ H₂₀ N₂ O₁₃having the formula:

O(OC)₂ C₆ H₃ COC₆ H₃ (CO)₂ NC₆ H₄ OC₆ H₄ N(OC)₂ C₆ H₃ COC₆ H₃ (CO)₂ O

EXAMPLE II Hemi-Amic Acid of Polyimide of Example I

Into the reaction equipment used in Example I there is placed 25 ml ofm-cresol, 4.04 gm of polyimide #1, 0.80 gm of N,N-methylallylamine andthe mixture is heated at reflux for one hour. Water:methanol (50:50) isadded to the precipitate and washes the polymer product which isisolated by filtration and dried in a vacuum oven at 130°-140° C. togive an almost quantitative yield of 4.38 grams. The elemental analysisof 68.1% carbon and 3.93% hydrogen are in good agreement with thecalculated values for C₅₄ H₃₈ N₄ O₁₃ having the formula: ##STR29##

EXAMPLE III Preparation of Anhydride-Terminated Polyimide #2

Using the m-cresol-benzene azeotropic procedure, there is allowed toreact benzophenone-tetracarboxylic acid anhydride (BTCA) (4.0279 g,0.0125 mole) and 1,3-di(3-aminophenoxy)benzene (DAPB-3,3) (2.9233 g,0.01 mole) in 40 ml of m-cresol and 10 ml of benzene. There is obtained5.76 gm of polyimide #2 which is a light yellow powder, soluble inm-cresol, DMAC, sulfolane and dioxane. In a Fisher-Johns melting pointapparatus, this melts at 200° C. The TGA in air shows losses at 200° C.of 1%, 3% at 300° C., 4% at 400° C., 5% at 500° C. and 17% at 600° C.The elemental analysis is: C: 71.4% and H: 3.2% which are in excellentagreement with the calculated values for C₁₅₇ H₇₈ O₃₅ N₈ of the formula:

O(OC)₂ C₆ H₃ COC₆ H₃ (CO)₂ [NC₆ H₄ OC₆ H₄ OC₆ H₄ N(OC)₂ C₆ H₃ COC₆ H₃(CO)₂ ]₄ O

EXAMPLE IV Preparation of Hemi-amic Acid of Anhydride-Terminated Polymer#2

Part A

In the same equipment used in Example I, there is added 5.28 g ofpolyimide #2, 40 ml of m-cresol and 0.30 gm of N,N-methyl-allyl amineand the mixture heated to 100° C. for one hour. A liquid sample is thenwithdrawn and analyzed. The elemental analysis is found to show C:71.00%, N: 4.97% and H: 3.67%, which values are in good agreement withthe calculated values for C₁₆₅ H₉₆ O₃₅ N₁₀ having the hemi-amic formula:##STR30##

Part B--Ester Derivative of Amide #2

The apparatus is converted by the addition of a Dean-Stark trap to acontinuous azeotroping apparatus. The trap is filled with toluene, 10 mlof benzene is added to the reaction mixture together with 5 ml of allylalcohol, and the reaction mixture is heated at reflux for 5 hours oruntil no more water of reaction is formed. Two grams of sodiumbicarbonate is added to the mixture to neutralize the toluene sulfonicacid. The solution is then filtered and concentrated on a rotaryevaporator and vacuum dried to constant weight at 130°-135° C. Theisolated product is washed with ether and redried in a vacuum oven. Theelemental analysis is found to give C: 71.59% and H: 3.81%, which valuesare in good agreement with the calculated values for the diamide-diesterC₁₇₁ H₁₀₄ O₃₅ N₁₀ having the formula: ##STR31##

On a Fisher-Johns melting point apparatus, the diamide-diester melts at190°-195° C., thickens above 210° C. and crosslinks and cures at210°-250° C.

EXAMPLE V Preparation of Hemi-Amic Acid Chloride

Part A of Example IV is repeated to obtain the hemi-amic which isisolated by evaporation of solvent from the reaction mixture and theresidue is washed with ether and dried. Then to a reaction flask isadded 53.5 gms of this hemi-amic, 250 ml of dioxane, an excess (10grams) of thionylchloride, and the mixture is refluxed until no more SO₂or HCl is liberated. The mixture is evaporated to dryness in a rotaryevaporator at 15 mm pressure to afford an almost quantitative yield (54g) of a product whose analysis shows 2.24% chlorine, which value is ingood agreement with the calculated value for the hemi-amic acidchloride: ##STR32## Instead of thionyl chloride, the phosphorous halidessuch as PCl₃, PCl₅, etc. can be used in the conversion of the acid tothe acid chloride.

EXAMPLE VI Conversion of the Hemi-Amic Acid Chloride to an Amide-Ester

In a suitable reaction flask, 20 ml of dioxane is added together with5.6 g of the acid chloride of Example V, 10 g of anhydrous methanol (anexcess) and 0.41 g of triethylamine in 5 ml of dioxane as a hydrohalideacceptor. The mixture is heated at reflux for 3 hours then precipitatedwith water, filtered, washed with methanol and dried to yield thediamide-diester: ##STR33## in which R is CH₃. When heated at 230° C. theamide-ester yields crosslinked polymers. Replacement of the methanol byother esterfiable ROH compounds yields the corresponding esters as shownin Table I. Isolation can also be achieved by precipitation with organicliquid in those cases where the ROH compound is not water soluble.

                                      TABLE I                                     __________________________________________________________________________    Amide #                                                                            ROH Used         R in Ester                                              __________________________________________________________________________    6    C.sub.2 H.sub.5 OH                                                                             C.sub.2 H.sub.5                                         7    C.sub.4 H.sub.9 OH                                                                             C.sub.4 H.sub.9                                         8    C.sub.12 H.sub.25 OH                                                                           C.sub.12 H.sub.25                                       9    CH.sub.2CHC.sub.6 H.sub.4 CH.sub.2 OH                                                          CH.sub.2CHC.sub.6 H.sub.4 CH.sub.2                      10   CH.sub.2CHC.sub.6 H.sub.4 OH                                                                   CH.sub.2CHC.sub.6 H.sub.4                               11                                                                                  ##STR34##                                                                                      ##STR35##                                              12   C.sub.6 H.sub.11 OH                                                                            C.sub.6 H.sub.11                                        13   C.sub.6 H.sub.5 CHCHCH.sub.2 OH                                                                C.sub.6 H.sub.5 CHCHCH.sub.2                            14   CH.sub.2CHOCH.sub.2 CH.sub.2 CH.sub.2 OH                                                       CH.sub.2CHOCH.sub.2 CH.sub.2 CH.sub.2                   15   CH.sub.2CHOC.sub.6 H.sub.4 OC.sub.6 H.sub.4 OC.sub.6 H.sub.4                                   CH.sub.2CHOC.sub.6 H.sub.4 OC.sub.6 H.sub.4                                   OC.sub.6 H.sub.4                                        16   CH.sub.2CHOOCC.sub.6 H.sub.4 OH                                                                CH.sub.2CHOOCC.sub.6 H.sub.4                            17   CH.sub.2CHCOOCH.sub.2 CH.sub.2 OH                                                              CH.sub.2CHCOOCH.sub.2 CH.sub.2                          18   CH.sub.2CHOC.sub.6 H.sub.4 OCH.sub.2 CH.sub.2 OH                                               CH.sub.2CHOC.sub.6 H.sub.4 OCH.sub.2 CH.sub.2           19   C.sub.6 H.sub.2 Cl.sub.3 OH                                                                    C.sub.6 H.sub.2 Cl.sub.3                                20   CHCCH.sub.2 OH   CHCCH.sub.2                                             21   CHCC.sub.6 H.sub.4 OH                                                                          CHCC.sub.6 H.sub.4                                      22   CHCCH.sub.2 C.sub.6 H.sub.4 OH                                                                 CHCCH.sub.2 C.sub.6 H.sub.4                             23   CHCC.sub.6 H.sub.4 CH.sub.2 OH                                                                 CHCC.sub.6 H.sub.4 CH.sub.2                             __________________________________________________________________________

Amides #6 through 23 crosslink when heated in the range of 200° to 350°C.; particularly suitable for preparing more highly crosslinked polymersare amides #10, #16, #17, #20 and #21.

EXAMPLE VII Conversion of the Hemi-Amic Acid Chloride To a TerminalDiamide

In a suitable reaction flask containing 20 ml of dry dioxane and usingthe procedure of Example VI, there is added together 5.4 g of the acidchloride of Example V, an equivalent amount of triethylamine (≃0.41 g)dissolved in 5 ml of dioxane as a hydrohalide acceptor and then anequivalent amount of the secondary amine. The mixture is reacted and theproduct isolated as described in Example VI. Table II lists the aminesreacted in individual reactions and the structure of the resulting amidegroup derived from the acid chloride function, such group being locatedterminally at the end of the chains, as given in the following equation:##STR36##

                  TABLE II                                                        ______________________________________                                        A-                                                                            mide                  New Amine                                               #    Amine Used (HNRR)                                                                              Group (CONRR)                                           ______________________________________                                        24                                                                                                   ##STR37##                                              25                                                                                  ##STR38##                                                                                      ##STR39##                                              26                                                                                  ##STR40##                                                                                      ##STR41##                                              27                                                                                  ##STR42##                                                                                      ##STR43##                                              28                                                                                  ##STR44##                                                                                      ##STR45##                                              29                                                                                  ##STR46##                                                                                      ##STR47##                                              30                                                                                  ##STR48##                                                                                      ##STR49##                                              31                                                                                  ##STR50##                                                                                      ##STR51##                                              ______________________________________                                    

Amides #24 to #31, inclusive, crosslink when heated in the range of 225°to 360° C.

EXAMPLE VIII

The procedure of Example IVA is repeated using diallylamine, HN(CH₂CH═CH₂)₂ instead of N,N-methylallylamine. The resultant hemi-amic acidis then converted to the acid chloride by the procedure of Example V toyield: ##STR52##

Reaction with the amines listed in Table II converts the acid chloridefunction to the corresponding type of amide groups listed in Table II,thus:

    ______________________________________                                         ##STR53##                                                                     ##STR54##                                                                    Amide #       New Amide Group (CONRR)                                         ______________________________________                                        33                                                                                           ##STR55##                                                      34                                                                                           ##STR56##                                                      35                                                                                           ##STR57##                                                      36                                                                                           ##STR58##                                                      37                                                                                           ##STR59##                                                      38                                                                                           ##STR60##                                                      39                                                                                           ##STR61##                                                      40                                                                                           ##STR62##                                                      41                                                                                           ##STR63##                                                      42                                                                                           ##STR64##                                                      ______________________________________                                    

It is to be noted that amide numbers 35, 36, 37, 38 and 40 have fourpolymerizable groups in each end-group on each chain end for a total ofeight polymerizable groups per chain.

Amides #32 to #42 inclusive, crosslink when heated in the range of 235°C. to 375° C.

EXAMPLE IX Preparation of Anhydride-Terminated Oligomeric Polyimide #3

Using the m-cresol-benzene azeotropic procedure, there is allowed toreact BTCA (3.6251 g, 0.01125 mole) and DAPB3,3 (2.9223 g, 0.01 mole) in40 ml of m-cresol and 10 ml of benzene. There is obtained 5.6071 g ofpolyimide #3 which is a light yellow powder soluble in m-cresol, DMAC,sulfolane and dioxane. On a Fisher-Johns melting point apparatus thismelts at 120° C. with some evolution of gas. The TGA in air shows lossesin air of 1% at 200° C.; 2% at 300° C.; 3% at 400° C.; 4% at 500° C. and19% at 600° C. The elemental analysis shows 71.01% C, 3.22% H and 4.60%N, which values are in excellent agreement with the calculated valuesfor the formula:

O(OC)₂ C₆ H₃ COC₆ H₃ (CO)₂ [NC₆ H₄ OC₆ H4OC₆ H₄ N(OC)₂ C₆ H₃ COC₆ H₃(CO)₂ ]₈ O

EXAMPLE X Preparation of Anhydride-Terminated Polyimide #5

Using the procedure of Example III, BTCA (14.50 g, 0.045 mole) isreacted with SDA (9.9324 g, 0.04 mole) in 90 ml of cresol and 20 ml ofbenzene. Polyimide #5 is obtained (21.4 g) which is a light yellow solidsoluble in m-cresol, DMAC, DMF and sulfolane. The lowest temperature atwhich a sample melts completely when dropped on a preheated block is270° C. Its TGA in air shows losses of: 0% at 200° C.; 2% at 300° C.; 3%at 400° C.; 4% at 500° C. and 25% at 600° C. The elemental analysisshows 63.99% C, 2.73% H and 4.95% N, which values are in good agreementwith the calculated values for the formula:

O(OC)₂ C₆ H₃ COC₆ H₃ (CO)₂ [NC₆ H₄ SO₂ C₆ H₄ (OC)₂ C₆ H₃ COC₆ H₃ (CO)₂]₈ O

EXAMPLE XI Preparation of Anhydride-Terminated Oligomeric Polyimide #6

Using the same azeotropic techniques as above, BTCA and2,4-diaminotoluene (DAT) are reacted in a molar ratio of six to five toobtain polyimide #6 whose elemental analysis conforms with the formula:

O(OC)₂ C₆ H₃ COC₆ H₃ (CO)₂ [NC₆ H₃ (CH₃)N(OC)₂ C₆ H₃ COC₆ H₃ (CO)₂ ]₅ O

EXAMPLE XII

Replacement of the BTCA in Example X by an equivalent amount ofpyromellitic dianhydride produces polyimide #7 which has the formula:

O(OC)₂ C₆ H₂ (CO)₂ [NC₆ H₃ (CH₃)N(OC)₂ C₆ H₂ (CO)₂ ]₃ O

EXAMPLE XIII

The anhydride-terminated polyimides #3, #4, #5, #6 and #7 are convertedindividually by the procedure of Example VIII to the diamide terminatedpolyimide corresponding to amides #35, 36, 38, 41 and 42. When heatedalone or with dicumyl peroxide, each of these yields an insoluble,infusible, crosslinked polymer.

EXAMPLE XIV

By the procedure of Example VIII, benzophenonetetracarboxylic aciddi-anhydride is converted to: ##STR65## This, when heated to 300° C.becomes infusible and insoluble in 40-60 seconds.

Other monomeric aromatic tetracarboxylic acid dianhydrides such aslisted above, may be substituted for the benzeophenonetetracarboxylicacid dianhydride to produce corresponding derivatives having 2-8terminal crosslinking groups.

Typical of the various other products of this invention that may beproduced by this procedure using monomeric dianhydrides are: ##STR66##

The above compounds may be mixed with unsaturated materials capable ofpolymerizing through its unsaturation and the crosslinking of suchcompositions is improved by the presence of such compounds to giveharder and more durable products upon molding. Moreover these compoundsmay be molded by themselves by the use of various polymerizationcatalysts, i.e. peroxy and other free radical generating materials togive satisfactory molded products.

EXAMPLE XV

The procedure of Examples III, IVA and IVB are repeated five timesexcept that an equivalent amount respectively is used of the followingindividual dianhydrides in place of the benzophenone-tetracarboxylicacid dianhydride used in Example III:

1. Pyromellitic dianhydride

2. 2,3,5,7-Naphthalene tetracarboxylic acid

3. 3,3'4,4'-Diphenyl tetracarboxyllic acid dianhydride

4. 2,2-Bis(3,4-dicarboxylphenyl)-propane dianhydride

5. Bis(3,4-dicarboxyphenyl)ether dianhydride.

The pyromellitic polyimide diaminde-diester product has the formula:##STR67## The other products have the same terminal groups as in theabove formula but have the following intermediate structuresrespectively:

2. >C₁₀ H₄ (CO)₂ [NC₆ H₄ OC₆ H₄ OC₆ H₄ N(OC)₂ C₁₀ H₄ ]₄ <

3. >C₆ H₃ -C₆ H₃ (CO)₂ [NC₆ H₄ OC₆ H₄ OC₆ H₄ N(OC)₂ C₆ H₃ -C₆ H₃ ]₄ <

4. >C₆ H₃ C₃ H₆ C₆ H₃ (CO)₂ [NC₆ H₄ OC₆ H₄ OC₆ H₄ N(OC)₂ C₆ H₃ C₃ H₆ C₆H₃ ]₄ <

5. >C₆ H₃ OC₆ H₃ (CO)₂ [NC₆ H₄ OC₆ H₄ N(OC)₂ C₆ H₃ OC₆ H₃ ]₄ <

EXAMPLE XVI

The procedures of Examples III, IVA, V and VII are repeated four timesexcept that an equivalent amount respectively is used of the followingindividual diamines in place of the 1,3-di(3-aminophenoxy)benzene usedin Example III and bis(4-vinylbenzyl)amine as the secondary amine usedin Example VII:

1. 4,4'-Diaminodiphenyl

2. 4,4'-Diaminodiphenyl methane

3. 4,4'-Oxydianiline

4. 4,4'-Diaminobenzophenone

The 4,4'-diaminodiphenyl polyimide tetramide product has the formula:##STR68## The other products have the same terminal groups as in theabove formula but have the following intermediate structuresrespectively:

2. C₆ H₃ COC₆ H₃ (CO)₂ [NC₆ H₄ CH₂ C₆ H₄ N(CO)₂ C₆ H₃ COC₆ H₃ (CO)₂ ]₄

3. C₆ H₃ COC₆ H₃ (CO)₂ [NC₆ H₄ OC₆ H₄ N(CO)₂ C₆ H₃ COC₆ H₃ (CO)₂ ]₄

4. C₆ H₃ COC₆ H₃ (CO)₂ [NC₆ H₄ COC₆ H₄ N(CO)₂ C₆ H₃ COC₆ H₃ (CO)₂ ]₄

EXAMPLE XVII

A mixture of 30 parts of polyimide-amide #10, 70 parts of long fiberedasbestos and 0.25 parts of cumyl peroxide is blended thoroughly andpreformed into a one-inch disc which is compression molded at 1000pounds per square inch at 265° C. for five minutes to yield a hardinsoluble, infusible, molded product.

Similarly, a glass fiber reinforced composite is prepared byimpregnating 181 E Glass Fabric with a solution of polyimide amide #10in N-methyl pyrrolidinone to a total resin content of about 35% and thesolvent removed by drying. The laminate is formed by stacking foursheets of impregnated glass fabric and curing at 250° C. at 200 poundsper square inch. The laminate is then post cured at 280° C. for 24 hoursand the cured product shows a flexural strength value in excess of45,000 psi.

Amide numbers 26, 27, 29, 35, 36, 38 and 42 also give similarsatisfactory molded and laminated products.

Of particular utility in the practice of this invention are thehemi-amic acid derivatives of Formula I, in which Y" represents OH or X.These can be converted to a large number of useful and valuablecompositions. For example, as shown herein above, the hemi-amic acidscan be converted to the hemi-amic acid halides which can and do reactwith active hydrogen containing compounds such as alcohols, amines andmany other compounds containing active hydrogen. The formula of thesehemi-amic acids can be written as: ##STR69##

The various symbols have the same definitions as given for Formula I andY" represents X or OH, with X representing halogen, of which chlorine ispreferred.

While the vinyl group (CH₂ ═CH--) has been designated as the terminalunsaturated group, it is also contemplated as within the scope of theinvention that substitution of small alkyl groups such as methyl, ethyl,etc. may be substituted for the alpha hydrogen in the vinyl group. Wheresuch substitution does not interfere with polymerization, thealpha-alkyl derivatives are equivalent to vinyl and may be used instead,such as alpha-methyl vinyl, alpha-ethyl vinyl, etc.

While certain features of this invention have been described in detailwith respect to various embodiments thereof, it will of course beapparent that other modifications can be made within the spirit andscope of this invention and it is not intended to limit the invention tothe exact details insofar as they are defined in the following claims:

The invention claimed is:
 1. A hemi-acid compound of the formula:##STR70## wherein: Ar' is a tetravalent aromatic benzenoid radical, thefour carbonyl groups being attached directly to separate carbon atomsand each pair of carbonyl groups being attached to adjacent carbon atomsin the Ar' radical except that in the case of the Ar' being anaphthalene radical one or both pairs of the carbonyl groups may beattached to peri carbon atoms;Ar is a divalent aromatic benzenoidradical; n is integer of at least one; R' is an organic moietycontaining 2 to 14 carbon atoms and having a terminal --CH═CH₂structure; said organic moiety consisting of a hydrocarbon radical ortwo or three hydrocarbon radicals joined by --O--, --SO₂ -- or --COO--groups R is an organic moiety containing one to 20 carbon atoms; saidorganic moiety consisting of a hydrocarbon radical or two or threehydrocarbon radicals joined by --O--, --SO₂ --, or --COO-- groups Y" is--OH or X; and X is a halogen.
 2. The hemi-amic acid compound of claim 1in which Y" is OH.
 3. The hemi-amic acid compound of claim 1 in which Y"is X.
 4. The hemi-amic acid compound of claim 3 in which X is chlorine.5. The hemi-amic acid compound of claim 4 in which R is R'.
 6. Thehemi-amic acid of claim 3 in which R' is --CH₂ CH═CH₂.
 7. The hemi-amicacid of claim 4 in which R' is --CH₂ CH═CH₂.
 8. The hemi-amic acid ofclaim 3 in which R is --CH₃.
 9. The hemi-amic acid of claim 4 in which Ris --CH₃.
 10. The hemi-amic acid of claim 4 in which R is --CH₂ C₆ H₄CH₂ CH═CH₂.
 11. The hemi-amic acid compound of claim 4 in which R is--CH₂ C₆ H₄ CH═CH₂.
 12. The hemi-amic acid compound of claim 5 in whichR and R' are --CH₂ CH═CH₂.
 13. The hemi-amic acid compound of claim 1 inwhich Ar' is a radical selected from the class consisting of: ##STR71##14. The hemi-amic acid compound of claim 1 in which Ar' is: ##STR72##15. The hemi-amic acid compound of claim 1 in which n is at least oneand the >N-Ar-N< is the residue of a diamine is selected from the classconsisting of:1,3- and 1,4-(NH₂)₂ benzene 2,3-; 2,5-; 2,6-and 3,5-(NH₂)₂toluene 3,3'-; 4,4' and 3,4'-methylene dianiline 4,4'-; 3,3'- and3,4'-oxydianiline; 4,4'-; 3,3'- and 3,4'-sulfonyldianiline; 1,3-; 1,4-and 1,2-bis(3-aminophenoxy)benzyene; and 1,3- and1,4-bis(4-aminophenoxy)benzene
 16. The hemi-amic acid compound of claim15 in which the diamine is a methylene dianiline.
 17. The hemi-amic acidcompound of claim 15 in which the diamine is a sulfonyl dianiline. 18.The hemi-amic acid compound of claim 15 in which the diamine is aoxydianiline.
 19. The hemi-amic acid compound of claim 15 in which thediamine is 2,5-toluene diamine.